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l>rEW TOEK STATE MUSEUM 



be set on each other setting the bricks of two successive courses 

 at right angles to each other. Each car carries about 360 brick. 

 Tracks are laid from the machines through the tunnels to"the 

 kilns. The tracks are laid in two directions only, at right angles 

 to each other, and turn tables are placed at the points where 

 tracks intersect. The tunnels are built of brick or wood. They 

 are about five feet high and four feet wide. Several methods 



Tunnel dryers. 



are used to heat the tunnels. There may be a fireplace at one 

 end and a system of parallel flues under the tunnel to conduct 

 the heat. A second method is to use steam heat, the pipes being 

 laid along underneath the floor of each tunnel or along the sides. 

 Exhaust steam is used in the day time and live steam during the 

 night. Another method is to heat the tunnel by a hot blast. In 

 a good dryer the natural draft should be sufScient to draw the 

 air through the tunnels. Six or more of these drying tunnels are 

 usually set side by side. Artificial drying takes from 24 to 36 

 hours. The green brick are put in at the end nearest the 

 machine and the cars with the dry ones drawn out at the 

 opposite end. It is of importance that the capacity of the dryers 

 should not exceed that of the kilns. Artificial dryers have the 

 advantage of permitting a plant to be run all winter. The cost 

 of flue dryers is set at 25 cents a thousand brick with coal at 

 $2.50 per ton. 



